Re: DAE solver with additional parameters

[Yu Liu]

I am not sure if this help, but how about using ode package that is similar to Matlab's solver.

http://octave.sourceforge.net/odepkg/function/ode45.html

You can pass additional parameters directly in the ode45 function call. Additionally, differential algebraic equations could be solved by the same function by using 'Mass' option, if your problem can be written in a compatible format.

On Tue, Jul 1, 2014 at 10:00 PM, lordgogi <address@hidden> wrote:

Hi,

I use Octave to simulate thermodynamic system. I have a set of DAE and solve
them with
dassl function. However I would like to pass additional parameters. Can
anyone help me with that? I also tried to use global variables but it does
not work either.

Thank you




Code:

x =
[A(1,12);A(1,11);A(1,3);A(1,5);A(1,10);eva_pressure_ini;0;-0;0;0;0;0.26;4];
xdot =
[7820.5;-0.053909;-0.83435;0.24349;0.53694;0.54863;8000;-3.867;0;4;0;0;0];
t = linspace(0,time_stop);
[x, xdot] = dassl("f", x, xdot, t);




/function res = f (x, xdot, t)
res (1) = xdot(9)+xdot(11)+xdot(7)-xdot(1);
res (2) = xdot(8)+xdot(10)-xdot(2);
res (3) = x(3)+x(4)+x(5)-x(2);
res (4) =
x(3)*XSteam('hL_p',x(6))+x(4)*XSteam('hV_p',x(6))+x(5)*XSteam('h_pT',x(6),450)-x(1);
res (5) = x(3)*XSteam('vL_p',x(6))+x(4)*XSteam('vV_p',x(6))-3;
res (6) = x(5)*XSteam('v_pT',x(6),450)-3;
res (7) = 8600-xdot(7);
res (8) =
-x(12)*sqrt(1.29*(2/(1.29+1))^((1.29+1)/(1.29-1)))*sqrt(x(6)/XSteam('v_pT',x(6),450))-xdot(8);
res (9) = xdot(8)*XSteam('h_pT',x(6),450)-xdot(9);
res (10) =x(13)-xdot(10);
res (11) = xdot(10)*XSteam('hL_p',x(6))-xdot(11);
res (12) = 0.00015*(x(6)-33)-xdot(12);
res (13) = 0.0005*(1596.7-x(3))-xdot(13);




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